@Kidany:
I'm gonna have to go with Aldrich on this one. You can't really say he has the offensive power of someone like Sanji when he can't even take out Spandam with his attacks. In the fights he's been in so far, he's never ended it with the use of his ammo.
Also "blasting Luffy from far away" wouldn't even really do much to him. Attacks that can pierce him are the best way to hurt Luffy, that's why Usopp used the shuriken star against him.Besides, even if Usopp got a good deal of distance between them, it's not like Luffy or anyone else would just stand there and let him.
He wasn't trying to KO Spandam, so it's a moot point. Plus, don't forget that Spandam took a "strong right" to the face and was still standing. One of Usopp's exploding stars is close in power to…let's say one of Sanji's nameless kicks.
As for Usopps strong attacks, what firebird star isn't strong? I mean, you're on fire. That hurts. And what if he has a bigger fire attack, I'm knid of expecting a "chou" (that means super right?) firebird star, using jet/flame dials for more power.
Now, what I meant eariler was, Usopp would be as strong as Zoro/Sanji from a distance is because most people, the marines in this case, would be helpless to fight Usopp from that distance--that is the distance he shot to save Robin. With Usopps accuracy, he'd be unstoppable because he's basically shooting fish in a barrel. Yet, when they all get close, Usopp like any sniper is dead.
Also, Alrich, as for Usopp being a real sniper, well, he'll never be a real sniper because he'll never use bullets. On the other hand, getting shot in the face with a tiny bomb should kill, maim, or cause some serious injury anyway. Like those guys Usopp shot in the mouth should have serious vocal chord damage. Actually, getting shot in the face with those bombs could cause serious eye injuries too, yet those guys are probably fine. It's just the nature of One Piece.
From what I gather, Usopp only needs bullets and blow heads up to be a sniper, I mean, that's all he's missing. But I can't see that happening in this manga. Usopp just has the accurancy right now.
As for Usopp missing ,well, I don't think snipers typically shoot fast moving targets so they? They wait for an opportunity and shoot someone in the neck. Come it think of it, shooting fast moving targets will probably be Usopp's "cutting through steel."